A lock nut (H), which has corresponding projections (IJ) is slipped over the post as shown at , and is given a quarter turn.
A lock nut, O, should be provided for this screw so that it will remain in adjustment.
Then a coupling is cut while screwed on a pipe, so that a lock nut about 1⁄2 inch wide is made.
When this adjustment is secured the lock nut is screwed in place so the needle valve will keep the adjustment.
A lock nut should be used in conjunction with this set screw.
The second nut is technically known as a “jam nut,” or “lock nut.”